A laser weapon is a type of directed-energy weapon (DEW) that uses lasers to inflict damage. Laser weapons are of two types: low-power laser dazzlers that blind optical systems or human eyes, and high-power lasers that can physically damage or destroy targets, such as enemy aircraft, drones, and missiles.

One of the major issues with laser weapons is atmospheric thermal blooming, which is still largely unsolved. This issue is exacerbated when there is fog, smoke, dust, rain, snow, smog, foam, or purposely dispersed obscurant chemicals present. In essence, a laser generates a beam of light that requires clear air or a vacuum to operate.

Low-power lasers have the potential to serve as non-lethal weapons. They can cause temporary or permanent vision loss. The extent, nature, and duration of visual impairment depend on factors including the laser's power, wavelength(s), beam collimation and orientation, and duration of exposure. Lasers with a power output of less than one watt can cause permanent vision loss. The Protocol on Blinding Laser Weapons bans weapons designed to cause permanent blindness. Weapons designed to cause temporary blindness, known as dazzlers, are in a separate category. Multiple incidents of pilots exposed to lasers while flying have been recorded.

High-power laser weapons capable of damaging or destroying a target are experimental as of 2026. The use of laser-beam weaponry to destroy aerial targets has been under development for years. The United States Navy tested short-range (1 mile), 30-kW Laser Weapon System or LaWS for use against targets such as small UAVs, rocket-propelled grenades, and visible motorboat or helicopter engines. A 60 kW system, HELIOS, was under development for destroyer-class ships as of 2020^[update]. India's DRDO successfully tested a 30 kW DEW, designated Mk-II (A) DEW, in April 2025 which could annihilate drones at a range of 5 km.

DEW for the destruction of incoming missiles are under development. One example is Boeing Airborne Laser, deployed inside a Boeing 747 and designated as YAL-1. This system was designed to eliminate short- and intermediate-range ballistic missiles during their boost phase. It was canceled in 2012.

Another system was studied under the Strategic Defense Initiative (SDI) and successor programs. This project aimed to employ ground-based or space-based laser systems to destroy incoming intercontinental ballistic missiles (ICBMs). However, various practical challenges, such as aiming a laser over a large distance through the atmosphere, complicated implementation. Optical scattering and refraction bent and distorted the beam, complicating aiming and reducing its efficiency.

A related concept was the nuclear-pumped X-ray laser, an orbiting atomic bomb surrounded by laser media in the form of glass rods. When a bomb detonated, the rods would be exposed to highly-energetic gamma-ray photons, causing spontaneous and stimulated emission of X-ray photons within the rod atoms. This process would result in optical amplification of the X-ray photons, generating an X-ray beam that was little affected by atmospheric distortion and capable of destroying ICBMs in flight. However, the X-ray laser became a single-use device, as it would destroy itself upon activation. Some initial tests were conducted with underground nuclear testing, but the results were not promising.

Iron Beam is a laser-based air defense system which was unveiled at the Singapore Airshow on 11 February 2014 by Israeli defense contractor Rafael Advanced Defense Systems. The system is designed to destroy short-range rockets, artillery, and mortar bombs; it has a range of up to 7 km (4.3 mi), too close for the Iron Dome system to intercept projectiles effectively. In addition, the system could also intercept unmanned aerial vehicles (UAVs). Iron Beam will constitute the sixth element of Israel's integrated air defense system, in addition to Arrow 2, Arrow 3, David's Sling, Barak 8, and Iron Dome.